1. Technical Field
The present invention relates to a positioning apparatus and a positioning method.
2. Related Art
Generally, in a method of acquiring position information by using a cellular phone, a GPS (Global Positioning System) is used, and the GPS is built in many cellular phones. In a place such as a building in a town or an indoor place in which the signal of the GPS is weak, it is difficult to automatically detect the position of a pedestrian carrying a cellular phone. As a method of solving such a problem, there is position measurement using autonomous navigation. As examples of technology relating to the autonomous navigation, there are JP-A-2-216011, JP-A-5-172579, JP-A-8-68643, JP-A-9-89584, JP-A-2007-218627, and “A Method of Map Matching for Personal Positioning Systems”, National Measurement Technology Convention Student Forum, 2001.
In JP-A-2-216011, JP-A-5-172579, JP-A-8-68643, and JP-A-9-89584, the autonomous navigation is performed by calculating a distance of movement of a pedestrian or the direction in which the pedestrian moves based on the movement of the observed pedestrian. In “A Method of Map Matching for Personal Positioning Systems”, National Measurement Technology Convention Student Forum, 2001, in order to eliminate error observed by the autonomous navigation, a map database is used in which a road network configured by nodes and edges and the boundaries and the areas of terrestrial objects located on the periphery thereof are represented. A correction method that is used when a pedestrian intersects with a peripheral boundary or when there is a big change in the direction of a pedestrian's body is proposed. In JP-A-2007-218627, in an environment in which a pedestrian normally moves within passages and enters into an area other than the passages at times, an apparatus that can calculate the movement history of a pedestrian with high accuracy by correcting the coordinates of the position of the pedestrian based on the pedestrian environment information, movement information acquired from the moving pedestrian, a pedestrian mode setting unit, and the like is proposed.
In JP-A-2-216011, JP-A-5-172579, JP-A-8-68643, JP-A-9-89584, JP-A-2007-218627, and “A Method of Map Matching for Personal Positioning Systems”, National Measurement Technology Convention Student Forum, 2001, methods of positioning the current position, the movement history, or the like of a pedestrian by observing the movement of the pedestrian by using various sensors are proposed. However, there is no technology taking advantage of information such as defects in a positioning environment, which was experienced in the past when the position was measured, when the position is newly measured. Accordingly, when the position is measured under various environments, there is a concern that a decrease in the accuracy of measurement experienced in the past may be repeated.